Embodiments of the present invention relate to techniques for displaying tomographic images of a slice in three-dimensional (3D) medical images.
There have been proposed a variety of kinds of image processing using a 3D medical image representing an anatomical part in a subject. Such image processing sometimes require processing of identifying a sice of interest in the 3D medical image, and reconstructing a tomographic image corresponding to the slice for display.
For example, in recent years, a process involving imaging an identical anatomical part in a subject by a plurality of imaging modalities, and presenting a resulting plurality of 3D medical images at the same time for reference has been practiced for the purpose of improving accuracy of image diagnosis. At that time, processing of registering the plurality of 3D medical images to align coordinate systems of the images with each other is generally applied. In registering 3D medical images with each other, for example, an image processing apparatus is arranged to identify, in two 3D medical images to be registered, candidate combinations of slices representing an identical portion of tissue common to the images, and reconstruct tomographic images corresponding to the slices for display. An operator refers to the tomographic images to visually identify a combination of slices possibly representing the identical portion of tissue. The image processing apparatus performs coordinate transformation on the 3D medical images so that tissue structures in the slices in the thus-identified combination positionally fit over each other.
In identifying a slice of interest in a 3D medical image and reconstructing a tomographic image of the slice for display, the slice width of the slice is generally set to a relatively small value, for example, of the order of 0.5 mm in a real space, to improve resolution of the tomographic image and enhance spatial resolution.
The smaller slice width of a slice to be identified, however, reduces information on tissue contained in the slice in a slice width direction, which makes it especially difficult to recognize a vascular structure serving as anatomical landmark. On the other hand, an excessively increased slice width lowers spatial resolution of the slice, which may be sometimes unsuitable for the purpose. Especially when registering 3D images with each other, this is an unfavorable factor leading to deterioration of precision of registration.
Under such circumstances, there is a need for a technique for displaying a tomographic image of a slice in a 3D medical image that allows better recognition of a vascular structure contained in the slice without degrading spatial resolution of the slice.